SAWS hopes to smoke out sewage leaks on North Side

SAWS contract worker Cameron Smith (left) and Alfredo Mata set up a blower fan as they get ready to conduct a smoke test on sewer lines along Rocky Oak Street in the city's North Central Side.

Photo By JERRY LARA

San Antonio Water System contractor Cameron Smith takes GPS coordinates of a leak while conducting a smoke test on sewer lines along Rocky Oak Street in the city's North Central Side on June 28. The process blows smoke into the sewer system which then makes its way through residential pipes. Smoke emanating from the ground pipes may indicate a possible leak in the system.

“Smoke testing helps to find leaks in private sewer lines that could allow wastewater to escape our system and go into the Edwards (Aquifer),” said Val Ruiz, SAWS vice president of Distribution and Collection Operations.

During the next four to five years, SAWS will smoke-test about 690 miles of pipe and the 52,000 private laterals that are attached to those lines above the aquifer recharge zone.

Businesses and residents will get a door hanger notification a few days before the crews show up.

The process is simple and has been used in the sewer industry for decades, Ruiz explained, but until now it has not been used to systematically test the sewer pipes in the recharge zone in San Antonio.

It's a common practice in the cities of New Braunfels, San Marcos and Austin.

Contactors seal off a couple blocks of sewer main and then drop in two sets of lit zinc chloride smoke bombs. Fans then push the smoke through the sealed-off sewer line and the laterals that are connected to it.

If there are no breaks, all of the smoke escapes out the plumbing vents of the buildings along that section of sewer main and the manhole covers. If there are breaks, the smoke will seep up through the ground.

If the break is at one of SAWS' lines, the utility will fix it. If the break is on private property, SAWS will mark it with a small red flag and leave a notice.

It then will send a notice to the property owner with pictures of the smoke informing them they have a year to have a licensed plumber inspect and fix the leak by TCEQ rules.

The testing is welcomed by the Greater Edwards Aquifer Alliance, as it will be the first time there will be inspections of the private laterals that connect to SAWS' sewer system.

“I'm glad they are putting in a safeguard,” executive director Annalisa Peace said.

Peace explained that in the porous limestone that defines the Edwards Recharge Zone, a private sewer pipe could easily have a break in it, allowing sewage to flow into the ground and the aquifer without any indication at the surface.

“Unless there was a blockage, you would never know it,” said Gerald Boman technical project manager for Burges & Niple which won SAWS' first pipe-smoking contract.

For more than a decade SAWS has been sending cameras through its mains to inspect for breaks, Ruiz said.

But that can cost anywhere from $2.50 to $7 a foot, Boman said, and can only be done on the publicly owned sewer pipes.

Smoking pipes cost 27 cents a foot, Boman said, and is a legal way for the city to check the private pipes that connect to its system.

A smoking crew can inspect almost two miles of sewer line a day, Boman said and will be constantly on the move.

Like any good prank, they should be able to drop their smoke bombs and be on the move to the next site before most folks realized they were there.